The present invention relates to a solid state laser device and, more particularly, to a solid state laser device including a light filter inserted between the pumping light source and the solid state laser element.
A solid state laser device having a solid state laser element the base of which is made of a yttrium aluminate crystal, is known to be useful because the oscillation light exhibits linear polarization due to the base crystal belonging to the orthorhombic system.
However, this type of laser device has not been put to practical use because the life of the base material is not long enough and the oscillation threshhold level, i.e., the minimum pumping level required to bring about laser oscillation, tends to rise with the lapse of time.